From ebb4f5e6e4cd68a856aeea5d319a76f47543c3a9 Mon Sep 17 00:00:00 2001 From: Tom Parkin Date: Fri, 24 Jul 2020 16:31:54 +0100 Subject: l2tp: don't BUG_ON seqfile checks in l2tp_ppp checkpatch advises that WARN_ON and recovery code are preferred over BUG_ON which crashes the kernel. l2tp_ppp has a BUG_ON check of struct seq_file's private pointer in pppol2tp_seq_start prior to accessing data through that pointer. Rather than crashing, we can simply bail out early and return NULL in order to terminate the seq file processing in much the same way as we do when reaching the end of tunnel/session instances to render. Retain a WARN_ON to help trace possible bugs in this area. Signed-off-by: Tom Parkin Signed-off-by: David S. Miller --- net/l2tp/l2tp_ppp.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'net/l2tp/l2tp_ppp.c') diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index 2aeee648c080..13c3153b40d6 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -1478,7 +1478,11 @@ static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs) if (!pos) goto out; - BUG_ON(!m->private); + if (WARN_ON(!m->private)) { + pd = NULL; + goto out; + } + pd = m->private; net = seq_file_net(m); -- cgit v1.2.3-59-g8ed1b